Existing automated media storage libraries are capable of storing and retrieving large quantities of information stored on media objects such as cartridges. This is accomplished by the use of a large number of cartridge storage cells, each of which houses a media cartridge, that are housed within an enclosure. Such storage libraries use a robotic mechanism (e.g., robot, picker, handbot, accessor, and the like) to quickly move the media cartridges between their media cartridge storage cells and media cartridge players. For example, to retrieve information that is stored on a selected media cartridge, a robotic mechanism moves to a location opposite the media cartridge storage cell housing the selected media cartridge. An end effector of the robotic mechanism then grasps the media cartridge and extracts it from the media cartridge storage cell to a media player where the end effector loads the media cartridge into the media player.
As automated storage libraries have become larger and more complex, their designs have evolved from a single robotic arm performing all media cartridge manipulations to multiple robotic mechanisms operating on several media cartridges and media players simultaneously. The ability to manipulate several media cartridges simultaneously has increased the throughput of the automated storage libraries. While one independent robotic mechanism is busy transferring one media cartridge from a media storage cell to a media player for mounting, a second independent robotic mechanism can be transferring another media cartridge to an access port, while a third robotic mechanism may be conducting an inventory of the storage library.
A typical automated storage library includes horizontally arranged support tracks laid throughout the storage library. The tracks are positioned along horizontally arranged rows of the storage library in the same plane of the rows. Each row includes multiple media cartridge storage cells. The media cartridge storage cells of the horizontally arranged rows form vertically arranged columns. The robotic mechanisms mount to the tracks to move horizontally along the rows throughout the storage library to access the media cartridges and the media players. The robotic mechanisms may include drive or propulsion means coupled to driving wheels for moving along the tracks. The robotic mechanisms may further include media object manipulation mechanisms such as media cartridge pickers or grippers, bar code reading devices, and other task oriented sub-modules for performing various tasks on media cartridges and media players.
It is generally desired that at least one robotic mechanism be mounted on a track associated with a media cartridge storage cell row of a storage library. For instance, if there are twelve media cartridge storage cell rows in the storage library then it is desired that there be twelve robotic mechanisms (one for each row or more for redundancy) in the storage library. Each robotic mechanism is a relatively expensive high performance device. Accordingly, a problem with having at least one robotic mechanism for each media cartridge storage cell row is the cost associated with such a relatively large number of robotic mechanisms.